Photo-mechanical resist



Patented May 8, 1934 UNITED STATES PATENT OFFICE PHOTO-MECHANICAL RESIST No Drawing. Application January 21, 1931, Serial No. 510,337

2 Claims.

This invention relates to a light sensitive layer and photo-mechanical resist such as is used in coating a metal, light printing the coating, developing, and then etching the metal surface.

It has been previously known that certain resin- 5 ous five-membered heterocyclic compounds can be used as photo-sensitive materials. The compounds of furfural with ketones have been given as examples, particularly furfural-acetone resin.

I have found that furfural acetone resin, on a metal plate, will give an imperfect print if the contact with the negative is good, because of the exclusion of air. Further, I have discovered that this resin will not print in the absence of oxygen.

If the oxidizing agent is incorporated with the resin when coated, the keeping qualities are not so good as if it is not present. The above diniculties can be overcome if the oxidizing agent is applied immediately before use as in a liquid coating. This will then be available to accelerate the 0 action in the absence of air due to good contact during printing.

A method of carrying out the invention is as follows:

A metal plate is coated with the following composition:

Resin (light sensitive) grams Acetone 100 0.0.

After the coating is dry it is then flowed with a little of the following solution:

Hydrogen peroxide 25 c. c. Glycerin '75 c. c.

The moistened metal plate is then printed in contact With a Waterproof line or halftone negative. Development is carried out as before.

Examples of oxidizing agents which are useful as above indicated are picric acid, hydrogen peroxide, and benzoyl peroxide, but other oxidizing agents can be used.

I consider as included within my invention all variations and equivalents coming within the scope of the appended claims.

What I claim is: 1. The process of making a photographic print that includes coating a suitable support with a light sensitive resinous heterocyclic compound, applying to the layer a coating of a liquid carrier and an oxidizing agent and exposing the coated support While still wet to a light image.

2. The process of making a photographic print that includes coating a suitable support with a light sensitive furfural acetone resin, applying to the layer a liquid coating comprising a carrier and an oxidizing agent and exposing the coated support while still wet to a light image.

ALEXANDER MURRAY. 

